I'd like to mention that combining the "ach_name" and "achievement" parameters into one as per Breakin'Benny's suggestion is a terrible idea.
Achievement icons on the wiki can either be PNGs or JPGs. Unless you can come up with a soft switch to enable the template to auto-detect extensions on the go, sticking with a separate icon value is preferrable.
Having the achievement name being the same as the icon also gives it .jpg or .png at the end. The icon itself also calls up an error as it looks for an <achievement name>.jpg.jpg file instead of just .jpg, because of the way the template is set up.
TL;DR: I'd much prefer the old version more than this one. Will be temporarily reverting to it since it works a lot better than the current iteration.
Are shptgun ammo's different amongst shotgun? If just on one or two or so it could be done the same as boosts, sights, scopes.
It's just not done on barrel extensions since the wide fluctuations on each and every one of them (though it seems less so since the rebalance, I feel a lot of fluctuation values of old are always the same now, like 4 stab for scopes or 4/8 for gadgets. Haven't seen an exception yet).